Apparatus and method for working a well with plural levels of perforations



Sept. 8, 1970 1 P. aRoussARn APPARATUS AND METHOD FOR WORKING A WELL WITH PLURAL LEVELS OF PERFORATIONS 2 Sheets-Sheet l Filed Aug. 9, 1968 @flea mIAWT/:s

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INVENTOR` LEO Fe BRoussARD BYoQwuJm-f Hls ATTORNEY Sept. 8, 1970 L.. P. BRoussARD APPARATUS AND METHOD FOR WORKING A WELL WITH PLURAL LEVELS OF PERFORATIONS Filed Aug. 9, 1968 2 Sheets-Sheet 2 IOX F l G. 5

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I NVENTOR:

HIS ATTORNEY United States Patent O ware Filed Aug. 9, 1968, Ser. No. 752,106 Int. Cl. E211) 33/124, 43/25 U.S. Cl. 166-297 10 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for completing a cased well extending into a hydrocarbon-bearing subterranean formation. A permanent indexer is set at a xed distance below a producing zone in the formation and the well casing is perforated at various levels in a predetermined pattern adjacent the producing zone. A straddle packing device having aperture means therein is extended into the Well to a position straddling the level of perforations in a manner sealing off one level of perforations from the other while aligning the aperture means with each level of the patterned perforations. Finally, aperture sealing means having at least one opening therein is moved via a tubing string axially within the well to a position aligning the opening with one level of the perforations while sealing off the remaining axially displaced perforations.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to well completion and, more particularly, to a method and apparatus for testing, treating and producing selective perforations within a Well.

Description of the prior art perforations may, for example, produce sand back into the well eventually plugging up the treated perforations.

SUMMARY OF THE INVENTION It is an object of this invention to provide a method and apparatus for selectively testing and treating perforations in a well.

It is a further object of this invention to provide a method and apparatus for isolating individual perforations of a well casing thereby precluding sand or other undesirable production from such perforations.

It is a still further object of this invention to provide a means for selectively testing, treating and producing perforations within a well without the necessity of removing any equipment from the well.

These objects are carried out by setting a permanent indexer a iixed distance below a producing zone in the formation. The well casing is then perforated in a predetermined pattern adjacent the production zone. A straddle-packing device having aperture means therein is extended into the vwell to a position straddling the perforations in a manner sealing off one perforation from the others while aligning the aperture means with each of the patterned perforations. Finally, aperture sealing means having at least one opening therein is moved axially within the well to a position aligning the opening with one of the perforations while sealing off the remaining perforations.

The apparatus comprises a permanent packer secured to the well casing a fixed distance below the zone to be perforated. The packer is used as an index for pattern perforating the formation. A straddle packer assembly having aperture means therein straddles each level of perforations with the aperture means aligned with the levels of perforations. The straddle packer assembly includes a selective positioning device fixed to its lower end which extends through the permanent packer. The positioning device includes spaced dog-legs and is closed at its lower end. The apparatus further includes a treating seal assembly having a port aligned with one level of the perforations and sealing means aligned with the remaining levels of perforations. The treating seal assembly extends through the permanent packer and the packer assembly. The lower end of the treating seal assembly includes indexing means adapted to engage the dog-legs of the positioning device as the treating seal assembly is moved, via a tubing string, axially in the borehole so as to selectively open each level of the perforations while sealing oft' the remaining axially displaced perforations.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 through 4 are `vertical sectional views of a preferred embodiment of the invention; and

FIG. 5 is a vertical sectional view of a modification of the embodiment of FIG. l.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, FIG. l shows a well borehole 10 extending into a subterranean hydrocarbon-y bearing earth formation 11. Hydrocarbon-producing zones, such as an oil shale formation 12, surround borehole 10. Well borehole 10 is preferably cased by casing 13 which may be sealed therein by cementing means 14. An indexer, such as a permanent wireline set indexerpacker 15, of any type well known to the art is anchored to casing 13 of the borehole 10 a predetermined fixed distance below formation 12. Packer 15 includes conventional slip means 16 and may include packer means 17 for engaging the inner wall of casing 13.

As shown in FIG. 2, producing zone .12 is pattern perforated; for reasons to be discussed further hereinbelow, zone 12 is preferably perforated in a predetermined manner, as for example, one perforation or levels of perforations every nine inches or so. Packer 15 may be used as an indexer for forming these perforations since the location and overall length of indexing packer 15 and the depth of producing zone is known. Thus, for example, perforations 19, 20 and 21 respectively, pass through cementing means 14 and casing 13 and the formation 12. Of course, there may be any number of perforations or levels thereof. Perforations 19, 20 and 21 may be formed by any of the known methods, such as by a jet or bullet perforating device 19a lowered by a cable 19b in well borehole 10 as is well known in the art. A straddle packer assembly 18 (FIG. 3) having a lower stinger portion 22 is lowered in borehole 10 by means of tubing 18a and ICC retained therein by means of conventional packer elehole that packer elements 23 straddle each perforation 19, 20 and 21. This may be accomplished by the aforementioned technique of relating the depth of Zone 12 to the packer 15. Openings 19a, 20a and 21a in straddle packer assembly 18 correspond with perforations 19, 20 and 21 respectively, when assembly 18, is aligned in position in borehole 10.

Lower stinger portion 22 comprises a selective positioning device 24 which extends through permanent packer 15. Positioning device 24 includes a plurality of preferably inset and outset profile configurations or spaced dog-legs 26a, 2611, 26C, 26d and 26e and is closed at its lowermost end by a conventional check valve 27. Dog-legs 26a through 26e are indexed in a predetermined manner with respect to perforations 19, 20 and 21, respectively, for reasons to be discussed hereinbelow. Thus, for each horizontally extending perforation there is an equivalent dog-leg, the distance between dog-legs corresponding to the distance between the perforations. Thus, dog-legs 26h, 26e and 26d correspond to perforations 19, 20 and 21, respectively. The uppermost dog-leg 26a corresponds to a position above all of the perforations and the lowermost dog-leg 26e corresponds to a position below all of the perforations for reasons to be discussed further hereinbelow. Valve 27 is disposed in positioning device 24 in such a manner that it closes when fluid pressure inside positioning device 24 exceeds uid pressure outside positioning device 24. Such a valve, as illustrated in FIG. 4, may comprise a conventional or retrievable ilapper Valve, ball valve or other check valve arrangement well known in the art.

A treating seal assembly 28 (FIG. 4) is disposed in well borehole 10 secured to the lower end 29 of a conventional pipe or tubing string 30 or secured to hydraulic motor assemblies (not shown) known to the underwater completion equipment art. Treating seal assembly 28 comprises an upper section 31 and a lower section 32. Upper section 31 extends through straddle packer assembly 18 and includes a plurality of packer elements 33 adapted to engage the inner surface of straddle packer assembly 18. As can be seen in FIG. 4, packer elements 33 are so arranged that each element 33 is aligned with a like packer element 23 of straddle packer assembly 18. The upper section 31 also includes aperture means adapted to be aligned with a corresponding perforation or perforation level when the packer elements 33 of the upper section 31 of treating seal assembly 28 are disposed adjacent their corresponding packer elements 23. Thus, as seen in FIG. 4, an aperture or port 34 is shown aligned with lower perforation 21. Obviously, treating seal assembly 28 may include a plurality of apertures 34 aligned with other of the perforations or perforation levels.

The lower section 32 of treating seal assembly 28 extends downwardly through the selective positioning device 24. The lower end of lower section 32 includes a resilient indexing member 35, for example, collet lingers with associated locks, adapted to engage dog-legs 26a through 26e of positioning device 24 as the treating seal assembly 28 is moved axially in well borehole 10. Thus, assuming an inset and outset profile configuration for dog-legs 26a through 26e, indexing member 35 would have a like inset and outset profile configuration adapted to mate and be retained within the appropriate dog-leg. For example, when port 34 is aligned with perforation 21 as in FIG. 1, member 35 engages the dog-leg 26d. Obviously, other congurations for member 35 and the dog-legs may be used, if desired.

In operation, well borehole 10 is extended into earth formation 11, cased and cemented therein by techniques well known in the art. An area of Well borehole 10, a fixed distance below, for example, formation 12, is indexed and may be packed off by means of indexer-packer as is also well known in the art (FIG. 1). The area of well borehole 10 adjacent the formation zone 12 is perforated in a known manner in a predetermined pattern as discussed hereinabove (FIG. 2) thereby forming any number of perforations 19, 20 and 21, respectively. The straddle packer assembly 18, having suflicient openings such as 19a, 20a and 21o therein, for any number of perforations or perforation levels is then lowered intoy well borehole 10 (FIG. 3) and secured to indexer-packer 15 through latch means 25a thus disposing straddle packer assembly 18 adjacent perforations such as 19, 20 and 21 in a predetermined manner. Accordingly, packer elements 23 of straddle packer assembly 18 straddle each perforation or level of perforations 19, 20 and 21. The openings 19a, 20a and 21a in straddle packer assembly 18 thus are aligned with the various levels of perforations 19, 20 and 21 respectively.

The straddle packer assembly 18, including selective positioning device 24, is secured to packer 15 through appropriate latch means such as 25 and 25a as can be seen in FIG. 4. The treating seal assembly 28 is then extended, by means of tubing string 30, or other suitable hydraulic means known in the well completion art, into well borehole 10 whereby the upper section 31 of treating seal assembly 28 is disposed adjacent perforations or perforation levels 19, 20 and 21 and the lower section 32 thereof is disposed within selective positioning device 24 (FIG. 4). The indexing member 35 of treating seal assembly 28 engages the lowermost dog-leg 26e of selective positioning device 24. In this lowermost position of indexing member 35, that is,'engagement with dog-leg 26e, the port 34 is now below all perforation levels and in this position provides a means of testing, with hydraulic pressure, various components and/or the absolute location of indexing member 35 since in this position all apertures including perforations are isolated. The position of the dog-leg 26d is so related to the lowermost perforation 21 that port 34, in treating seal assembly 28, is aligned with perforation 21 while packer elements 33 of treating seal assembly 28 are aligned with packer elements 23 of straddle packer assembly 18. In this manner, only a single perforation may be open to treatment. Individual perforations, as for example, the remaining perforations 19 and 20, may be selectively tested and treated by moving treating seal assembly 28, by means of tubing string 30, or suitable means, axially within borehole 10. The indexing member 35 of treating seal assembly 28 selectively engages the remaining dog-legs 26C and 2Gb and retains treating seal assembly 28 so that individual perforations may be tested and treated. Thus, as shown in FIG. 4, the apparatus is in the test-treat position and only perforation 21, aligned with port 34, is being treated. At the topmost position of indexing member 35, that is, in engagement with dog-leg 26a, the port 34, previously used for treating, is now above the straddle packer assembly 18 thereby permitting the circulation of fluid between the annulus (formed between the tubing string 30, straddle packer assembly 18 and casing 13) and the tubing string 30 (through port 34) while all the perforations are isolated.

After selectively treating individual perforations, perforations that failed to accept treatment may be isolated by inserting a blank section of a production seal assembly opposite the untreated perforations. This is illustrated in FIG. 5 wherein like numerals refer to like parts of FIGS. l through 4. In this feature of the invention, the treating seal assembly 28 of FIG. 4 has been replaced by a production seal assembly 36 secured to the lower end 29 of tubing string 30 and retained in position by mechanical or hydraulic means, for example, latch 42a engaging slip means 42 in straddle packer 18. Production seal assembly 36 includes a plurality of packer elements 37, similar to packer elements 33, aligned with packer elements 23 of straddle packer assembly 18 when set in place. Production seal assembly 36 includes a plurality of ports, such as ports 38- and 39, aligned with perforations 19 and 20. A blank section 40 of production seal assembly 36 is aligned with perforation 21 since, for example, it may have been previously determined that perforation 21 failed to accept treatment. Perforations that, again for example, were found to have accepted treatment, such as perforations 19 and 20, may be produced through slotted intervals (that is, ports 38 and 39) of production seal assembly 37 opposite the treated perforations 19 and 20. In practice, the production seal assembly may be obtained by eliminating the lower section 32 of the treating seal assembly 28 of FIG. l. The ports 34, 38 and 39 may comprise, selectively, a combination of either ported or blank sections of seal assemblies or other closure means so that various perforations, singularly or in combination, may be selectively test-treated, isolated or produced.

lf selective retreatment, such as acidizing, is required at `a later date, a conventional work string may be run through the production tubing with a treating seal assembly similar to assembly 28 but with a smaller upper section 31 to permit packer elements similar to 33 to engage the inner surface of treating seal assembly 28 and individual treated perforations may be treated by moving the selective positioning device 24 below the straddle packer assembly 18 in the manner discussed hereinabove. In addition, the special treating seal assembly hereinabove described ean be deposed through the production tubing utilizing other suitable hydraulic means hereinabove mentioned to effect retreatment in various applications, such as underwater `well completions, without necessitating removal of the production tubing or use of macaroni tubing or use of a workover rig. One such treatment process utilizing the apparatus and method of this invention is disclosed in a copending application, Ser. No. 849,178, tiled Aug. 11, 1969. In this application, a Well testing and sand consolidation process is disclosed which may be carried out using the techniques disclosed hereinabove.

The apparatus and method disclosed herein provides a selective means for testing, and/or treating, and/ or isolating, and/or producing perforations or perforation levels, whether circular or slotted in nature, on an individual basis during initial completion of any zone or zones in a well bore and further provides a selective means for retesting, and/ or retreating, and/ or re-isolating, and/or reopening to production perforations or perforation levels on an individual basis during any subsequent remedial operation of any zone or zones in a well bore by selectively positioning and repositioning special seal assemblies (treating, isolating or producing) utilizing conventonal mechancal means such as tubing movement or other means such as hydraulic pistons (motors) used to position other types of tools in underwater well completions with or withf out necessitating use of a workover rig depending on apparatus arrangement selected. Assuming proper selection of apparatus arrangement, the method disclosed herein may be effected on single or multiple zones and, further, multiple zones may selectively be produced or isolated (including any number of associated testing and treating remedial operations) thus permitting any number of completions and/or recompletions in a Wellbore.

Various techniques of carrying out the concepts of this invention may become apparent to one skilled in the art and it is to be understood that such modications fall within the spirit and scope of the appended claims.

l claiin as my invention:

1. A method for completing a cased well extending into a hydrocarbon-bearing subterranean formation comprising the steps of setting a permanent indexer having a plurality of indexing portions therein at a fixed position below a producin g interval in said formation;

perforating said Well casing adjacent said producing interval in a predetermined pattern `with respect to Said indexing portions thereby forming a plurality of levels of perforations in a pattern communicating with said interval;

extending a straddle packing device having axially displaced aperture means therein into a position within said Well straddling the perforations in a manner sealing olf the space between the interior of the casing and the exterior of the device between each perforated level of casing while aligning the aperture means with each of said patterned levels of perforations; moving aperture sealing means via a tubing string having both an indexing member adapted to engage said indexing portions and at least one opening therein axially within said well and the interior of the device to a position aligning the opening with one level of said aperture means while sealing olf the remaining axially displaced aperture means when said indexing member engages one of said indexing portions; and

moving said aperture sealing means axially in said well to a position -whereby said indexing member engages the remaining indexing portions of said indexer thus aligning said opening with each level of said aperture means thereby selectively treating all of said levels of aperture means.

2. The method of claim 1 including the step of pumping fluid down said tubing string and out through said openings and into said formation to treat said perforated formations.

3. The method of claim 1 including the steps of:

determining which of said levels of perforations failed to accept uid entry and exit out of the formation in the foregoing steps; and

isolating any of said perforations which failed to accept uid by inserting a blank section of said aperture sealin g means opposite any of said perforations which failed to accept uid.

`4. A method for completing a cased well extending into a hydrocarbon-bearing subterranean formation comprising the steps of:

setting a permanent indexer having a plurality of indexing .portions therein producing interval in said formation; perforating said well casing adjacent said producing interval in a predetermined pattern with respect to said indexing portions thereby forming a plurality of levels of perforations in a pattern communicating With said interval; extending a straddle packing device having axially displaced aperture means therein into a position Within said well straddling the perforations in a manner sealing olf the space between the interior of the casing and the exterior of the device between each perforated level of casing while aligning the aperture means with each of said patterned levels of perforations;

moving aperture sealing means via a tubing string having both an indexing member adapted to engage said indexing portions and at least one opening therein axially within said Well and the interior of the device to a position aligning the openng with one level of said aperture means while sealing off the remaining axially displaced aperture means when said indexing member engages one of said indexing portions;

moving said aperture sealing means axially in said well to a position where said opening therein is disposed above all of said perforations thereby isolating all of said perforations; and

circulating uid down the annulus formed between said casing, said tubing string, and said straddle packing device while all of said perforations are isolated.

5. A method for completing a cased well extending into a hydrocarbon-bearing subterranean formation comprising the steps of setting a permanent indexer having a plurality of indexing portions therein at a iixed position below a producing interval in said formation;

perforating said well casing adjacent said producing interval in a predetermined pattern with respect to said indexing portions thereby forming a plurality of levels of perforations in a pattern communicating with said interval; extending a straddle packing device having axially displaced aperture means therein into a position within said Iwell straddling the perforations in a manner sealing 01T the space between the interior of the casing and the exterior of the device between each perforated level of casing while aligning the aperture means with each of said patterned levels of perforations; moving aperture sealing means via a tubing string having both an indexing member adapted to engage said indexing portion and at least one opening therein axially within said well and the interior of the device to a position aligning the openng with one level of said aperture means while sealing olf the remaining axially displaced aperture means when said indexing member engages one of said indexing portions; and moving said aperture sealing means axially in said well to a position wherein said opening is disposed below all of said perforations, thereby isolating both said perforations and communication between the annulus formed between said tubing string, said straddle packing device and said casing and the tubing string. 6. Apparatus for working a well extending into a pattern perforated producing zone of differing levels in a hydrocarbon-bearing subterranean formation, said apparatus comprising:

permanent packing means disposed in said well a fixed distance below said producing zone; straddle packing means having aperture means therein disposed in said well in a position straddling said patterned perforations in a manner sealing off one level of perforations from the other while aligning said aperture means with each of said patterned levels of perforations; aperture sealing means secured to a tubing string disposed in said well having at least one opening therein and adapted to be moved axially within said well to a position aligning said opening with at least one level of said perforations while sealing off the remaining levels of perforations; said straddle packing means including a selective positioning device having a plurality of dog-legs therein disposed in said vwell below said perforated zone in 8 such a manner that the position of said dog-legs in said well is related to the position of the levels of perforations in said pattern-perforated zone and the distance between said dog-legs corresponds to the distance between said levels of perforations; and said aperture sealing means includes an indexing member adapted to engage said dog-legs whereby said opening in said aperture sealing means is selectively aligned with the perforated level corresponding to the opsition of said dog-leg.

7. The apparatus of claim 6 including a check valve disposed at the lowermost end of said selective positioning device.

8. The apparatus of claim 6 whereby said selective positioning device includes at least one dog-leg corresponding to a point in said well above the uppermost perforated level in said perforated zone.

9. The apparatus of claim 6 wherein said straddle packing means includes a plurality of packer means engaging the inner wall of said well disposed in a pattern adapted to straddle each of said patterned perforations; and

said aperture sealing means includes a plurality of packer means in such a pattern that said second-mentioned packer means is adapted to be aligned with said irstmentioned packer means when said aperture sealing means engages said straddle packing means.

10. The apparatus of claim 6 `wherein said aperture sealing means includes a plurality of openings adapted to be aligned with a plurality of said levels of perforations.

References Cited UNITED STATES PATENTS 2,963,088 12/1960 Coney 166-313 X 2,973,039 2/1961 Payne.

3,384,170 5/1968 van Poolen 166-191 X 3,398,796 8/1968 Fisher et el. 16e-120 3,412,805 11/1968 Gribbin et el. 16s- 147 x 3,424,246 1/1969 Myers 166-127 MARVIN A. CHAMPION, Primary Examiner I. A. CALVERT, Assistant Examiner U.S. Cl. X.R. 

